Osbourne, Iommi, Butler and Ward reunited for Live Aid in 1985 and for the climax of Ozzy's No More Tours Tour in 1992, but neither had resulted in an album or tour. An attempt at a reunion in 1993 proved abortive – and, when Osbourne, Iommi and Butler reunited as Sabbath for the 1997 Ozzfest, Ward was replaced by Faith No More's Mike Bordin.
Concern about Ward's health meant former Sabbath drummer Vinny Appice was on standby for two homecoming shows at the Birmingham NEC on December 4 and 5, 1997. "We hadn't done a show with Bill for 18 years," remarked Iommi. In fact, Ward made it through both shows – albeit not without incident. "Bill hit a gong and it fell on him," Iommi reported. "I creased up. His arm was black and blue in the morning, because those things weigh a ton. When it hit him and fell onto the kit, it sounded like someone was throwing pots and pans around. We were waiting for something like that to happen."
Along with live versions of classics such as "Paranoid", "N.I.B.", "Black Sabbath" and "Iron Man", the double album features two new studio tracks: "Selling My Soul" and "Psycho Man". The two new tracks on Reunion were also released on a single CD in the USA.
Sabbath received their first Grammy Award for Best Metal Performance, for the live recording of "Iron Man" from this album in 2000. They won the same award 13 years later, for "God Is Dead?".